One usual arrangement is for pairs of chains to be guided through upper forwarding runs along tracks in a common plane and through lower return runs, around drive sprockets on a common axis between the runs at one end of the conveyor, and around return sprockets on another common axis between the runs at the other end of the conveyor. The closeness of the transverse spacing of the flights on the conveyor chains is limited by the widths of the chains and the necessary clearance between them, which imposes a limit on the minimum width of container (or length of sleeve carton) that can be handled by the conveyor. There is, of course, no theoretical limit to the maximum lateral spacing of the flights, and adjustment of the spacing between the practical limits can be readily effected by providing for adjustment of the drive and return sprockets along their respective axes and possibly also with adjustment of the lateral spacing of the guide tracks for the upper forwarding run.
Another known arrangement has a pair of chains carrying propelling flights and an intermediate chain carrying leading flights, the chains again being guided through upper forwarding runs along guide tracks in a common plane and through lower return runs, with drive and return sprockets on respective common axes between respective ends of the runs.
It is also feasible, with some containers or products, to use two chains, one carrying propelling flights and the other carrying leading flights, again with guide tracks in a common plane for forwarding runs and drive and return sprockets on respective common axes between respective ends of the forwarding runs and the return runs for the chains.
Again, in either case, there is a limit imposed on the closest transverse spacing of the flights by the widths of the chains.